Method of treating sound records and records produced thereby



Sept; 22, 1931. T, TAYLOR 1,824,417

METHOD OF TREATING SOUND RECORDS AND RECORDS PRODUCED THEREBY Filed Jan. 31, 1930 EIUEIEIDUUDEID Patented Sept. 22, 1931 UNITED STATES PATENT v OFFICE ALFRED T. TAYLOR, OF BEVERLY HILLS, CALIFORNIA, ASIGNOR TO METROfGOLDWYN- MAYER CORPORATION, 'OF CULVER CITY, CALIFORNIA, A CORPORATION OF NEW I YORK \ METHOD OF TREATING SOUND RECORDS AND RECORDS PRODUCED THERmY Application filed January 31,1930. Serial No. 425,035.

This invention relates to a method of treatmg sound records; and particularly sound records bearing thereon variable density impressions representing sound waves or oscillatory currents ofvarying frequencies. The

out the method embraced by this invention.-,

Sound records of the character particularly adapted for treatment in accordance with the method to be described hereinafter and embraced by this invention, are records produced by a modulated light upon a sensitive film emulsion on a substantially transparent base. Records of this character are generally known as variable density records, and comprise striations extending transversely to the longitudinal axis of the continuous film. Said striations occur in the continuous film spaced from each other at varying distances, said distances or periods depending upon the speed or rate of movement of the film during recording and the frequency of the recorded oscillations.

In this manner the spacing of said striations is a function of the frequency of the sounds recorded on the film. By passing such a variable density record in front of a-narrow slit through which a constant beam of light is being passed, the light is modulated,-

and in this manner a modulated light is projected upon a photo-electric or other light sensitive cell adapted to generate an oscillatory current comparable to the frequencies recorded upon the record and to the fre quencies of the soundsforiginally recorded thereon.

When films of the hereinabove described character are connected to each other, a splice results which is more opaque than the rest of the film. Furthermore, the Sp ice is of appreciable width and when suc splice passes in front of a constant light source, it modifies the light passing through the film and causes the photo-electric cell or other reproduclng mechanismto be influenced by said splice. In this manner a splice creates an audible click Such clicks and splice-marks are of high amplitude and it is impossible at the present time to transfer a record from a film onto a wax recording without causing such maximum amplitude changes to influence the wax {ecordings and very often render them useess.

When a splice sound of high amplitude is reproduced the vibration set up in the stylus recording the sounds upon a wax reco'rd is suflicient to cause the stylus to-leave its individual groove and engage with or cross-an adjoining groove.

Heretofore, extraneous sounds accidentally recorded upon a continuous film record of the character .described hereinabove could not be removed without cutting the film and splicing it, such splices as has been explained before, being disadvantageous. If it was desired to insert a particular section of sdund record onto a continuous film, it was necessary to make two splices, one at each end of the insertion made into the continuous film. Anobject of this invention is to disclose and provide a method for making .a quiet splice in a sound recording.

Another object is to disclose and provide a method whereby continuous sound recordings maybe corrected without the creation of spliced sound records.

Another object is to disclose and provide a method of splicing films which is substantially invisible and which does not createextraneous sounds when the record is reproduced.

A still further object is to disclose and provide a method of inserting sound records into A still further object is to. disclose and pro- 16 modified forms, and of the result which may be attained thereby. 4

In describing the invention, reference will be had to the appended drawings, in which: Fig. 1 is a front View of a combined picture and sound recording, showing the film or record produced in accordance with this invention.

Fig. 2 is an enlarged view of a splice connecting two continuous sound records.

Fig. 3 shows two continuous films bearin sound records connected in accordance wit this invention. I

Fig. 4 represents a continuous sound record in which an extraneous sound has been recorded.

Fig. 5 represents a sound record such as that shown in Fig. 4, which has been treated in accordance with the method of this invention so as to remove the extraneous sound.

By the term splicing or spliced as usedherei'n, reference ismade to the act of scraping,cutting and cementing film together, whether said film bears thereon a sound record, a picture record, or a combination of both picture and sound records. During splicing operations the emulsion on one of the films is generally scraped off and occasionally-one or more of the ends of the film records which it is desiredto connect are beveled. A cementing fluid is then applied, said fluid generally comprising or containing amyl-acetate or other suitable solvent which permits the cellulosic backings to weld together. Generally, the total width of the splice ranges from about 1/10th to 2/10ths of an inch.

As shown in Fig. 2, the continuous film 1 is cemented or spliced to a continuous film 2 so as to form an overlapping joint 3. films 1 and 2 bear a sound record thereon, the film 1 bearing thereon a longitudinal strip 4 having transverse striations 5 of greater density than the intermediate portlons 6 or the portion 7 which does, not bearany striations at all. The horizontal striations 5 represent the nodesot an oscillatory current,'the spacing being dependent upon the frequencies of the oscillatory current. The'area 'l' merely bears a record of the car.- rier wave or unmodulated'light which normally passes through the light valves (used in recording) when an oscillatorv current is not passing through said light valves. The areas, such as 7, give rise to-what is known as surface or ground noises.

It will be seen that at 3 two sharp lines The Y extend through the sound record, these lines representing the edges of the overlapped film. Such lines will, during reproduction, cause the photo-electric cell, or other reproducing means, to be energized thereby causing a sharp aperiodic click to be reproduced, such click or noise being of volume usually equal to the normal level of the film record. Such noises are highly undesirable, particularly as a thousand-foot reel often contains as many as one hundred such splices, each of which reproduces as a loud clicking noise. One of the objects of this invention is to permit a splice or joint to be made which will not cause the 1m to give rise to such extraneous noise. In carrying out the method of my invention, a film may be joined or spliced in the ordinary manner and, therefore, the film will first assume the character shown in Fig. 2. A section is then cut from the joined films 1 and 2, the section taking the form of one half cycle ofa sine wave, the wave having a height or amplitude equivalent to the width of the sound record 4, and'a period or length equivalent to a frequency of 25 cycles, or any other frequency substantially below the normal range of audibility. More correctly, the section takesthe form of four-sixths of a complete sine wave composed of one maximum positive value and two maximum negative values, such curve starting and terminating at zero. The maximum amplitude of the section thus cut from the film should .occur at the splice 3 so that the overlapping or doubled thickness of film in the splice is removed in the sound record proper 4. Preferably, the sine wave section thus cut from the film includes a datum section extending into the film" and away from the sound record so as to form-shouldersB with an edge 9 parallel to the longitudinal axis of the sound record 4, but spaced therefrom.

The edges 10 and 11 of the section thus cut out of the film are in the form ofa half cycle sine wave, the edge 10 extending from one side of the record to the other side and assuming the form of one-half cycle. (from a maximum negative value to a maximum positive value) ota sine wave of a frequency below normal audibility,'whereas the edge 11 is in the form of the other half of a cycle of such a sine wave (from the maximum positive value to the maximum negative value). A section 12 identical to the segment-cut out of the. joined films 1 and 2 and'described hereinabove, is also out out of a single s'eparate piece offilm, said section being either transparentior of a density substantially equivalent to the carrier wave or surface noise density 7 of the record 4. The section 12 thus cut from a separate piece of film is then introduced into the aperture cut from the joined'films 1 and 2, said section 12 fitting exactly into said aperture. A small coming an integral part of the continuous film. said cement being substantially transparent. The line along which the joint occurs is normally substantially invisible and, therefore, does not reproduce when the films thus joined and treated are passed through a reproducing apparatus. Even. though the joint would be opaque, no audible sound would result, particularly if'the density of the two joined film records and the inserted section is substantially the same, as the frequency of the reproduced sound wave of the section 12 is below the normal rangeof audibility.

Attention is called to the fact that the section 12 needs preferably be in the form of an For example, if the tion 12 assumes the form of an equi-lateral triangle, and if the joints formed at those edges are opaque, then there maybe a tendencyfor said joint to reproduce a harmonic of the frequency represented by the amplitude and period of the section thus inserted.

If the edges 10 and 11 are sine curves,however, and even though'the section '12 were completely opaque,.then only the fundamental of the frequency represented by the section 12 would be reproduced, and inasmuch as said frequency is below the normal ran e of 'audibility, no extraneous noise would reproduced when such a film is passed through a reproducing mechanism.

The method described hereinabove is not limited in its application to splices or joints in the film. If, forexample, a film such as the sound record illustrated in" Fig. 4 is encountered, said sound record bearing thereon a record of a desired frequency represented by the striations 13, in which an extraneous noise has been inadvertently recorded as indicated at 14, such record may be corrected so that the extraneous noises or sound recorded at 14 is eliminated. This can be accomplished in the following manner:

A sine wave section is cutout of-the film or sound record shown in Fig. 4, said section comprisinga front edge 15 having the form of half a cycle of a sine wave of a fre uency below normal audibility, and extending from one edge of the sound record tothe other so as to have an amplitude equivalent to the width of the sound record, and a rear edge 16 in the form of the other half of the cycle of such sine wave.

The crest of thesine wave section represented by the edges 15 and 16 may be separated by a distance Y equivalent to the length of the record embracing the false note or extraneous noise, such as the recording 14. The

entire section thus cut out preferably also includes the datum portion 17, although such datum portion may be eliminated, the elimination of the datum portion 17 making it more difiicult to insert and retain the very narrow pointed ends of the sine Wave section cut out and subsequently inserted.

A section 18 indentical in contour and length to the section thus cut out of the film or sound record is then cut out of another sound record bearing thereon the required striations or frequencies For example, the

section 18 preferably bears thereon a variable densit recordof a note or sound having the same requency as the sound recorded and indicated at 13. The record on the section 18 may be indicated by the striations 13'. The section 18 is then inserted carefully into the aperture cut into the sound record illustrated in Fig. 4, and welded in place by the applica tion of a suitable film cement such as amylacetate.

It is to be understood that the joints formed by the insertion of the incomplete sine curve sections into the apertures cut into the sound records are abutted joints, preferably, and not overlapped joints, so that the thickness of. the film is not varied. As a result of the hereinabove described operations, a record such as is shown in Fig. 5 results, from which the extraneous sounds or noises, such as those indicated by the recording at 14 have been removed.

It is to be'understoodthat the method described hereinabove is not only applicable to the performance of the acts and the attain- -ment ofthe results described in the above examples, but may also be applied in numerous other instances. The method may be employed in overcoming splice noises, re-

moving surface noises, removing a portion of a record, removing an error in a record, removing a portion of the record andinserting a section which bears no recording, removing damages in the record, removing a portion of the sound record and inserting a correction, or making other changes in the recordings produced originally.

Sound recordings are preferably origin- I ently great to intersect and cross an adjoining groove inthe spiralrecording being cut in the disc. It is likely then that when such a record is played the reproducer needle will not track properly in the groove and will continue either to play in one groove steadily or jump over the adjoining groove entirely.

If the original sound recording on the continuous film is treated in accordance with the methods embraced by this invention, then said continuous sound record may be safely employed in the reproduction of the sounds for recording on a disc, cylinder or other wax record.

When the method embraced by this invention is applied to sound records carried by a continuous film which also carries picture records (such asthe film shown in Fig. 1),

then it is preferable to position the datum.

section away from the perforated edge of the film and permit the crest of the sine curve sections cut out and inserted into the sound record to adjoin that edge of the record which in turn adjoins the perforations. This arrangement and position of the sectionsdoes not decrease the strength of the film and obviates the tendency for the film to separate or tear at that portion where such sections have been cut out and inserted.

The methodsembraced by this invention maybe varied somewhat as will be apparent to those skilled in the art, and the invention is not limited to the precise sequence of operations, length and form of the sections cut out or inserted into the sound record, or the precise purpose of said acts specifically men-- tioned hereinabove.,- The invention includes all such changes and modifications as come within the scope of the appended claims.

'1. A method of treating spliced continuous sound records, comprising removing a section of thesound record at a splice, said section being in the form of a half cycle sine curve with its crest at the splice, the sine curve having an amplitude substantially equivalent to the width of thevsound record and a period equivalent to a vibration of frequency below normal audibility, and then inserti and cementing a section of film similar in contour to the removed section into said sound record.

2. A method of treating spliced continuous sound records, comprising removing a section of the sound record at a splice. said section being in the form ofa half cycle sine-curve with its crest at the splice, the

sine having an. amplitude substantially equivalent to the width of the soundrecord and a period substantially equivalent to a vibration of frequency below normal audibility,

cutting a section identical in contour and size to said removed section from a separate sound record, and inserting and cementing said separate section into the aperture formed by the removal of said first section from said record.

3. A method of treating continuous films bearing sound recordings thereon so as to remove extraneous recordings therefrom, comprising cutting a section from said sound record, said section being in'the' form of a half cycle sine curve with its crest at the point where the extraneous record is located,

said sine curve having an amplitude substan tially equivalent to the width of the sound the section removed from said sound record I being treated, and inserting and cementing said separate section in the aperture formed in said sound record to be treated.

4. A method of treating continuous films bearing sound recordingsthereon and including extraneous recordings, comprising removing a section of the sound record to be treated, said section being in the form of a half cycle sine curve with its crest at the point where the extraneous sound records are located, said sine curve having an amplitude substantially equivalent to the width of the sound recordand a period equivalent to a vibration below normal audibility, cutting a section from a separate film bearing a desired sound record thereon, said separate section 4 being identical in size and configuration tothe first section removed from the film to be treated, and inserting and cementing said separate section in the aperture formedin the sound record to be treated.

5. A continuous sound record including a section:of diflerent material bodilyinserted thereinto, said section having the form of a half cycle sine wave.

6. A sound record comprising a continuous strip of material having a variable density sound record thereon, and an insertion made in said record, said insertion having the form of a half cycle sine wave.

7. A spliced sound record comprising two continuous strips of material having variable density sound records thereon connected together. and an insertion ofhalf cycle sine wave form carried by said stripe ,at their point. of connection.

8. A spliced sound record comprising two continuous strips of material having variable density sound records thereon connected togetheryand an insertion of half cycle sine wave form made in said sound recordsat their polnt of connection, the crest of said sine wave insertion being substantially in alinement with said splice.

- 9. A sound record comprising a continuous strip of material .having variable density sound records thereon, and aninsertion made. in said sound record, said insertion having the form of a half cycle sine Wave and beaning a variable density sound record.

10. A sound record comprising a continuous strip of material having a Variable density sound record thereon, and an insertion made in said sound record, said insertion having the form of a half cycle sine Wave and bearing a variable density sound record in synchronism With the record on said continuous strip 11. A sound record including a section inserted thereinto,- said section having the form of an incomplete sine wave having a fire quency below normal audibility, and an amplitude equivalent to the Width of the sound record.

Signed at Culver City, California this 18th day of December, 1929.

ALFRED T. TAYLOR 

